Refactor Prometheus Adapter to take in cluster

What does this MR do?

1st part of #119297 (closed)

Refactor Prometheus Adapter to take in cluster instead of deployment_platform. This allows us the choice not to call project.deployment_platform which could be incorrect if that is called after the deployment has been done.

Does this MR meet the acceptance criteria?

Conformity

• [-] Changelog entry
• [-] Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• [-] Database guides
• [-] Separation of EE specific content

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.